GB1398184A - Sensing apparatus - Google Patents
Sensing apparatusInfo
- Publication number
- GB1398184A GB1398184A GB2824372A GB2824372A GB1398184A GB 1398184 A GB1398184 A GB 1398184A GB 2824372 A GB2824372 A GB 2824372A GB 2824372 A GB2824372 A GB 2824372A GB 1398184 A GB1398184 A GB 1398184A
- Authority
- GB
- United Kingdom
- Prior art keywords
- current
- circuit
- component
- transistor
- log
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/02—Measuring effective values, i.e. root-mean-square values
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
- Measuring Volume Flow (AREA)
Abstract
1398184 Measuring rms and mean values of current waveforms WESTINGHOUSE ELECTRIC CORP 16 June 1972 [23 July 1971] 28243/72 Heading G1U The rms value of a current from a current transformer 1, Fig. 1, is determined by rectifying 6 the current, causing it to flow through a load 16 comprising two transistors 12, 14 connected as diodes, using the resulting voltage across the load - which will vary substantially logarithmically with the current - to control, by means of a transistor 24, the current in a second circuit 22, which also includes a transistor 26 connected as a diode, shunting the alternating component of the current in the second circuit away from the diode connected transistor 26 by a capacitor 28 connected either across the transistor 24, in which case the A.C. component circulates around transistor 24 and capacitor 28, or across the transistor 26 as in Fig. 2, (not shown) in which case the A.C. component flows through a loop including transistor 24 and capacitor 28, and measuring 21 the resulting direct current flowing in the second circuit. A modified circuit Fig. 3, (not shown) includes a switch whereby either the rms or the mean value of the unknown current can be determined, the action of the switch being effectively to connect capacitor 28 across the meter 21, thereby to shunting the A.C. component of the current in the second circuit around the meter but allowing it to pass through the diode connected transistor 26. An approximate analysis of the circuit shown in Fig. 1 is as follows. Let i x be the instantaneous value of the rectified unknown current; let i = i o + i ac be the instantaneous value of the current in the second circuit, where i o is the D.C. component and i ac is the A.C. component, and assume that the A.C. component flows entirely around the loop consisting of transistor 24, capacitor 28. Then the voltage across the first circuit, ie between conductors 8 and 10, can be derived in two ways: firstly as the voltage across the load 16, which is - log k 1 i x + log k 2 i x where k 1 and k 2 are constants associated with transistors 12 and 14; and secondly as the emitterbase voltage plus the diode voltage in the second circuit, which islog k 3 i + log k 4 i o where k 3 and k 4 are constants associated with transistors 24 and 26. In practice all the above k's may be assumed to be substantially unity, so thatlog i x + log i x. = log i + log i o ie, i x <SP>2</SP> = ii o . But i = i o + i ac, and 1/T#<SP>T</SP> O ix<SP>2</SP> dt =1/T#<SP>T</SP> O i o <SP>2</SP> dt + 1/T#<SP>T</SP> O i o i ac dt hence, =i o <SP>2</SP> providing that T is the period of the alternating component i ac and is substantially constant over such period. Thus the D.C. component i o of the current in the second circuit 22 is a measure of the rms value of the current in the first circuit 16. When capacitor 28 is connected across the diode connected transistor (26), Fig. 2 (not shown) the A.C. component also flows through the meter 21 which must therefore be sufficiently damped to indicate only the D.C. component. The current whose rms value is determined could, of course, be derived from a voltage source Fig. 2 (not shown).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16546271A | 1971-07-23 | 1971-07-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1398184A true GB1398184A (en) | 1975-06-18 |
Family
ID=22598991
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2824372A Expired GB1398184A (en) | 1971-07-23 | 1972-06-16 | Sensing apparatus |
Country Status (9)
Country | Link |
---|---|
US (1) | US3743949A (en) |
JP (1) | JPS5744945B1 (en) |
BR (1) | BR7204883D0 (en) |
CA (1) | CA951793A (en) |
DE (1) | DE2235944A1 (en) |
ES (1) | ES404957A1 (en) |
FR (1) | FR2147140B1 (en) |
GB (1) | GB1398184A (en) |
IT (1) | IT962856B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2183048A (en) * | 1985-11-11 | 1987-05-28 | British Gas Plc | Method and apparatus for testing AC generators |
WO1997020369A1 (en) * | 1995-12-01 | 1997-06-05 | Berg Technology, Inc. | Method of making smooth contact terminals |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4027240A (en) * | 1975-10-20 | 1977-05-31 | The United States Of America As Represented By The Secretary Of The Navy | Protected voltage meter |
US4218736A (en) * | 1978-04-03 | 1980-08-19 | Takeda Riken Kogyo Kabushikikaisha | Effective value measuring apparatus |
JPS556066A (en) * | 1978-06-29 | 1980-01-17 | Seiko Epson Corp | Production of fluid passage |
US4375038A (en) * | 1979-08-10 | 1983-02-22 | Beckman Instruments, Inc. | RMS Converter |
CN1020816C (en) * | 1990-05-08 | 1993-05-19 | 董献之 | Square arithmetic unit |
GB2262350B (en) * | 1991-11-22 | 1995-11-08 | Multiload Technolgy Ltd | RMS Waveform sensing |
WO1996024070A1 (en) * | 1995-01-30 | 1996-08-08 | Landis & Gyr Utilities Services, Inc. | Method of sizing transformers in an electrical utility service |
ES2623844T3 (en) | 2003-07-25 | 2017-07-12 | Waste 2 Green, Llc | Procedure and system for the treatment of waste material from animals containing urea |
CN102207518A (en) * | 2011-03-11 | 2011-10-05 | 华为技术有限公司 | Method and device for detecting effective value of alternating current (AC) voltage |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3070302A (en) * | 1958-08-15 | 1962-12-25 | Phillips Petroleum Co | Flow computer |
US3064192A (en) * | 1959-03-10 | 1962-11-13 | Gen Electronic Lab Inc | Electric meter |
US3197626A (en) * | 1962-01-08 | 1965-07-27 | Chrysler Corp | Logarithmic multiplier-divider |
US3281689A (en) * | 1962-03-26 | 1966-10-25 | Expando Meter Company | R. m. s. meter circuit using linear resistors and voltage biased diodes to approximate the square law characteristic |
FR1486264A (en) * | 1965-07-08 | 1967-10-05 | ||
US3423578A (en) * | 1966-08-29 | 1969-01-21 | Chrysler Corp | True root-mean-square computing circuit |
-
1971
- 1971-07-23 US US00165462A patent/US3743949A/en not_active Expired - Lifetime
-
1972
- 1972-06-16 GB GB2824372A patent/GB1398184A/en not_active Expired
- 1972-06-22 CA CA145,356,A patent/CA951793A/en not_active Expired
- 1972-07-14 IT IT26998/72A patent/IT962856B/en active
- 1972-07-17 ES ES404957A patent/ES404957A1/en not_active Expired
- 1972-07-20 JP JP47072121A patent/JPS5744945B1/ja active Pending
- 1972-07-21 BR BR4883/72A patent/BR7204883D0/en unknown
- 1972-07-21 DE DE2235944A patent/DE2235944A1/en active Pending
- 1972-07-24 FR FR7226576A patent/FR2147140B1/fr not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2183048A (en) * | 1985-11-11 | 1987-05-28 | British Gas Plc | Method and apparatus for testing AC generators |
GB2183048B (en) * | 1985-11-11 | 1989-12-20 | British Gas Plc | Method and apparatus for testing ac generators |
WO1997020369A1 (en) * | 1995-12-01 | 1997-06-05 | Berg Technology, Inc. | Method of making smooth contact terminals |
Also Published As
Publication number | Publication date |
---|---|
BR7204883D0 (en) | 1973-06-07 |
US3743949A (en) | 1973-07-03 |
FR2147140A1 (en) | 1973-03-09 |
CA951793A (en) | 1974-07-23 |
FR2147140B1 (en) | 1978-12-29 |
JPS4822072A (en) | 1973-03-20 |
ES404957A1 (en) | 1975-07-01 |
DE2235944A1 (en) | 1973-02-01 |
IT962856B (en) | 1973-12-31 |
JPS5744945B1 (en) | 1982-09-24 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
CSNS | Application of which complete specification have been accepted and published, but patent is not sealed |